a. Field of the Invention
This invention relates to an improvement in the cut-off device for binding machines of the type wherein a sheaf of papers is compressed between a male spine having a series of studs which extend from the spine, through perforations in a sheaf of paper, and then into a mating female spine; the female spine must be supported at spaced intervals and the excess stud length cut off. In a preferred embodiment of the invention, the cut-off device is utilized with binding elements wherein the studs have ratchet teeth and the female spine has a mating tooth with a blocking element which moves into place behind the stud to hold the ratchet teeth in engagement.
B. Description of the Prior Art
The closest known prior art is U.S. Pat. No. 3,608,117 wherein a heated cut-off device is used to sever an excess spine length in a binding machine. In said patent, a heated knife severs the excess stud length some distance from a female binding element whereby there is left a short, heat-softened stub which can be swaged into a rivet head in a subsequent operation. The knife element does not support the female spine and an independent means of support must be employed. The present invention differs from this prior art patent primarily in that (a) the knife of the present invention provides at least partial support for the female binding element while the parts are in compressed condition, (b) the knife of the present invention severs the excess spine flush with the female binding element, and (c) the knife of the present invention is not heated.